1. Field of the Invention
This invention relates to a composition comprising an ion exchange resin with a ligand ionically bonded thereto with the ligand coordinately bonded to a transition element and with the transition element also bonded to the resin.
2. The Prior Art
The use of heterogeneous catalysts over homogeneous catalysts has several advantages such as allowing the use of fixed beds, ease of separation of catalyst from the product and catalyst recovery and regeneration.
Traditionally, to produce heterogeneous catalysts from metals of the transition element series, these metals have been deposited on inert supports such as alumina or slica. More recently metal catalysts have been covalently attached to inert resin backbones by use of diphenylphosphine or other ligands which are attached directly to the polymer and coordinately bonded to the metal. Typical examples of this type are found in U.S. Pat. No. 3,998,864, issued Dec. 21, 1976, and in Pittman et al, Chemtech, p. 560-566, 1973.
Application Ser. No. 861,916, filed Dec. 19, 1977, disclosed a composition comprising an ion exchange resin with an organic linking compound ionically bonded thereto and with the linking compound further coordinately bonded to a transition element metal. The composition of this invention, on the other hand, not only has the transition element bonded to the linking compound but also to the resin. This dual bonding of the metal provides additional stability. The composition of this invention is much more leach resistant with regard to the transition metal than conventional heterogeneous transition metal catalysts. The materials of this invention are also relatively simple to prepare using commercially available compounds. Their preparations involve no exotic conditions and often times may be carried out in an aqueous solvent system and the resins may be easily stripped of metal and ligands for isolation of the metal species and regeneration of the catalyst. The resin based catalysts of this invention have unique selectivity-reactivity properties when compared to their homogeneous analogues.